Water Resources Department.
Presenter:
Shuwan Jawdat Barzanjy
Seismic analysis for dam safety ensures structures can withstand earthquakes, preventing catastrophic failures, floods, and infrastructure loss. It involves evaluating dynamic stability, potential deformations, and structural integrity under safety evaluation earthquake (SEE) ground motions, often using finite element analysis (FEA) to simulate behavior.Core Components of Seismic Dam AnalysisDesign Earthquakes:Operating Basis Earthquake (OBE): Expected seismic shaking during the life of the dam, designed to cause minimal damage.Safety Evaluation Earthquake (SEE/MCE): The most severe earthquake considered for the site, focusing on preventing catastrophic failure, even if significant repairs are needed.Methods of Analysis:Dynamic Analysis (Time Domain): Preferred for large dams to model non-linear structural behavior, crack propagation, and stress over time.Pseudo-Static Analysis: Traditional, simpler method using horizontal acceleration coefficients ((0.1g) or higher) to simulate seismic forces, though less accurate than dynamic modelling.Safety Considerations:Soil Properties: Assessment of liquefaction potential, cohesion, and plasticity in embankment dams.Dam-Reservoir Interaction: Dynamic water pressure effects are modeled, particularly in concrete dams.Monitoring: Acceleration, velocity, and deformation are monitored to compare against numerical models.Key Failures to Prevent:Embankments: Cracking, slumping, and overtopping due to settlement.Concrete Dams: Cracking, spalling, and instability of monolithic blocks.Key Seismic GuidelinesICOLD Bulletin 148: Selecting Seismic Parameters for Large Dams.FEMA Federal Guidelines: Earthquake Analyses and Design of Dams.Common safety criteria require that dams remain functional or maintain controlled release during/after the maximum design earthquake.
05/05/2026
